Various surgical procedures are performed by medical specialists such as cardiologists and radiologists, utilizing percutaneous entry into a blood vessel. To facilitate cardiovascular procedures, a small gauge needle is introduced through the skin and into a target blood vessel, often the femoral artery. The needle forms a puncture through the blood vessel wall at the distal end of a tract that extends through the overlying tissue. A guide wire is then introduced through the bore of the needle, and the needle is withdrawn over the guide wire. An introducer sheath is next advanced over the guide wire; the sheath and guide wire are left in place to provide access during subsequent procedure(s). The sheath facilitates passage of a variety of diagnostic and therapeutic instruments and devices into the vessel and its tributaries. Illustrative diagnostic procedures include angiography, intravascular ultrasonic imaging, and the like; exemplary interventional procedures include angioplasty, atherectomy, stent and graft placement, embolization, and the like. After this procedure is completed, the catheters, guide wire, and introducer sheath are removed, and it is necessary to close the vascular puncture to provide hemostasis and allow healing.
The most common technique for achieving hemostasis is to apply hard pressure on the patient's skin in the region of the tissue tract and vascular puncture to form a blood clot. Initially, pressure is applied manually and subsequently is maintained through the use of mechanical clamps and other pressure-applying devices. While effective in most cases, the application of external pressure to the patient's skin presents a number of disadvantages. When applied manually, the procedure is time-consuming and requires the presence of a medical professional for thirty minutes or more. For both manual and mechanical pressure application, the procedure is uncomfortable for the patient and frequently requires the administration of analgesics to be tolerable. Moreover, the application of excessive pressure can occlude the underlying artery, resulting in ischemia and/or thrombosis. Even after hemostasis has apparently been achieved, the patient must remain immobile and under observation for hours to prevent dislodgment of the clot and to assure that bleeding from the puncture wound does not resume. Renewed bleeding through the tissue tract is not uncommon and can result in hematoma, pseudoaneurisms, and arteriovenous fistulas. Such complications may require blood transfusion, surgical intervention, or other corrective procedures. The risk of these complications increases with the use of larger sheath sizes, which are frequently necessary in interventional procedures, and when the patient is anticoagulated with heparin or other drugs.
In recent years, several hemostasis techniques have been proposed to address the problem of sealing vessel wall punctures following percutaneous transcatheter procedures. Related prior art is described in U.S. Pat. Nos. 5,320,639; 5,370,660; 5,437,631; 5,591,205; 5,830,130; 5,868,778; 5,948,425; 6,017,359; and 6,090,130. In each of these patents, bioabsorbable, thrombogenic plugs comprising collagen and other materials are placed proximal to the vessel wall puncture site to stop bleeding. The large hemostasis plug stimulates blood coagulation in the vessel puncture site, but blocks the catheter entry tract, making catheter reentry more difficult, if required.
Other related prior art disclosed in U.S. Pat. Nos. 5,707,393; 5,810,884; 5,649,959; and 5,350,399 provides for the use of small dissolvable disks or anchors that are placed in the vessel to block or clamp the puncture hole. However, any device remaining in the vessel lumen increases the risk of thrombus formation. Such a device also can detach and cause occlusion in a distal blood vessel, which would likely require major surgery to remove.
Additional prior art includes U.S. Pat. Nos. 5,779,719; 5,496,332; 5,810,850; and 5,868,762. In the disclosure of these patents, needles and sutures delivered through catheters are used to ligate the puncture. The suturing procedure requires particular skill. Suture material left in the vessel may cause tissue irritation that will prolong the healing process.
Still other prior art is disclosed in U.S. Pat. No. 5,626,601, wherein a procoagulant is injected into the puncture, with a balloon catheter blocking inside the vessel lumen. However, in some cases, the clotting agent may leak past the balloon into the vessel lumen and cause stenosis.
Yet other prior art references related to this topic include U.S. Pat. Nos. 4,929,246; 5,810,810; and 5,415,657, which disclose the use of a laser or of radio-frequency (RF) energy that is transmitted to the blood vessel through a catheter to thermally fuse or weld the punctured tissue together.
All of the above cited prior art references require either introducing and leaving foreign objects in the patient's body, and/or inserting a tubular probe of large diameter into the tissue channel left by the catheter in order to seal the puncture.
As will be evident from the preceding discussion, there is a clear need for an improved method and apparatus for sealing a puncture left in a blood vessel, following an intravascular catheterization procedure. The method and apparatus should cause rapid cessation of bleeding, not rely on blood clot formation, and should be independent of the patient's coagulation status. By employing such a method and apparatus, the patient will be more comfortable as a result of shortened hemostasis and ambulation times, and physician and hospital resources will thereby be minimized. In addition, the method and apparatus should not leave any foreign object in the patient's body, to reduce the risk of stenosis at or distal to the puncture wound. An ideal device will be noninvasive and should not include any component that must be inserted in the catheter tract and which might further damage the wound and impede the sealing process.